Our Box Two tier's mission in life is to deliver performance similar to the Box One but without its exotic (and costly) features. You still get the Tri-Pack™ Clutch in our derailleur only it isn't adjustable. The cassette's 11-50T range is equally impressive but we don't cut it out of a single block of steel. The action on the shifter is just as snappy although you don't get the rigid die-cast pull lever. The chain boasts the same unique ability to mate with a wide/narrow chainring except you give up the trick DLC top coat. You're hardly shortchanging yourself with Box Two. INCLUDES Box Two Prime 9 Multi Shift Shifter Box Two Prime 9 X-Wide Rear Derailleur Box Two Prime 9 11-50T Cassette Box Two Prime 9 126L Chain Nickel Box One Shift Cable & Housing Kit SUPPORT MATERIAL View Prime 9 Drivetrain Compatibility Manual View Prime 9 Comparison Chart Why Prime 9?